Fuel Efficient GDI Engines Are Dirtier

Researchers at the University of Toronto’s Faculty of Applied Science & Engineering looked at the emissions from gasoline direct injection (GDI) engines, which are smaller and more efficient than traditional petrol engines.

Car manufacturers have adopted GDI engines in models to satisfy demand for more miles per gallon, and increased power output. According to the team, the number of GDI engines found in new cars between 2009 and 2015 has jumped to from five per cent to 46 per cent.

But their analysis revealed while carbon dioxide emissions were lower in GDI engines, they pumped out more soot and harmful organic compounds such as benzene and toluene.

‘The whole motivation for creating these engines in the first place was fuel efficiency. But what we haven’t considered are the other climate-related emissions,’ explained Professor Greg Evans, an engineer and applied chemist at Toronto.

‘If a vehicle emits a small amount of soot, it can completely negate the lower amount of CO2 that it’s emitting.‘